Legend not changing colors in ggplot2 - r

Question

I am trying to plot a scatter plot with 22 variables, so they all need to have different markers. I thought of repeating some shapes and colors from RColorBrew, and everything works fine, except for the legend that does not update with the colors I selected (please see image below). I also attached a working example below. What could I possibly be doing wrong?
#!/usr/bin/env Rscript
library(ggplot2)
library(ggpubr)
library(RColorBrewer)
theme_set(
theme_pubr()
)
data <- data.frame(
x = c(1:22),
y = as.factor(c(1:22))
)
shapes <- rep(15:18, 6)
colors <- rep(brewer.pal(n = 11, name = "Paired"), 2)
plot <- ggplot(data, aes(x=x, y=y, group=y, size=9, color=colors)) +
geom_point(aes(shape=y)) +
scale_shape_manual(values=shapes) +
scale_size(guide="none") +
guides(fill="none", color="none")
plot <- plot + theme(panel.grid.major=element_line(colour="gray", size=0.2),
panel.grid.minor=element_line(colour="gray", size=0.2))
print(plot)

Answer 1

There are two issues:
I you want to have your colors make use of scale_color_manual and map y on the color aes as you did with shape
The reason your legend does not get colored is that you have set guides(color = "none")
library(ggplot2)
library(ggpubr)
library(RColorBrewer)
theme_set(
theme_pubr()
)
data <- data.frame(
x = c(1:22),
y = as.factor(c(1:22))
)
shapes <- rep(15:18, 6)
colors <- rep(brewer.pal(n = 11, name = "Paired"), 2)
plot <- ggplot(data, aes(x = x, y = y, group = y, size = 9)) +
geom_point(aes(shape = y, color = y)) +
scale_shape_manual(values = shapes) +
scale_color_manual(values = colors) +
scale_size(guide = "none") +
guides(fill = "none")
plot + theme(
panel.grid.major = element_line(colour = "gray", size = 0.2),
panel.grid.minor = element_line(colour = "gray", size = 0.2)
)

Answer 2

I found a number of things going on. I broke them down one by one here:
You're including colors in the aes but it's not a part of the data, it's just the color palette, so that shouldn't be included here. aes is telling ggplot what data to show, not how to format it.
geom_point needs both a color and shape aes argument so that it can combine them and later tell the legend how it has done so.
To control the color palette used, I added scale_color_manual, similar to how you were already using scale_shape_manual to manually adjust formatting
Remove the guides line at the end. by setting color = "none" it's blocking color from being added to the legend.
Try the segment of code below.
data <- data.frame(
x = c(1:22),
y = as.factor(c(1:22))
)
shapes <- rep(15:18, 6)
colors <- rep(brewer.pal(n = 11, name = "Paired"), 2)
#OLD: plot <- ggplot(data, aes(x=x, y=y, group=y, size=9, color=colors)) +
plot <- ggplot(data, aes(x=x, y=y, group=y, size=9)) +
#OLD: geom_point(aes(shape=y)) +
geom_point(aes(shape=y, color=y)) +
scale_shape_manual(values=shapes) +
#NEW LINE
scale_color_manual(values = colors) +
scale_size(guide="none")
# REMOVED guides(fill="none", color="none")
plot <- plot + theme(panel.grid.major=element_line(colour="gray", size=0.2),
panel.grid.minor=element_line(colour="gray", size=0.2))
print(plot)